WoW is way better.
I played WoW beta. I have 4 lvl 40+ chars, one lvl 50 + on L2. The lvling is WAY slow and the PvP is terrible on L2. IF you turn red in L2 and get killed by a white, you can lose a lot of equipment and you lose a lot of exp. You kill a white, they lose no items.
However, turning a high lvl red and using crappy equipment you dont mind losing and killing rpging carebears is hella fun.
